1. Technical Field
The present invention relates to a capacitive touch screen and a method for manufacturing the same.
2. Description of the Related Art
With the development of a mobile communication technology, user terminals such as cellular phones, PDAs, and navigations can serve as a display unit that simply displays character information as well as a unit for providing various and complex multi-media such as audio, moving picture, radio internet web browser, etc. Due to a recent demand for a larger display screen within a terminal having a limited size, a display scheme adopting a touch screen has been more in the limelight. The touch screen integrates a screen and coordinate input units, thereby making it possible to save a space as compared to a key input scheme according to the prior art.
A type of current mainly used touch screen is largely classified into two types.
First, a resistive touch screen has a shape in which an upper substrate formed with an upper resistive film and a lower substrate formed with a lower resistive film are spaced from each other by a spacer and are disposed to be in contact with each other by external pressure. When an upper substrate formed with an upper electrode film is pressed by an input unit such as fingers, pens or the like, the upper/lower electrode films are conducted and a change in voltage according to a change in resistance value of the positions is recognized by a controller, such that the touched coordinates are recognized.
A capacitive touch screen has a structure in which an upper substrate formed with a first electrode pattern having a first directionality and a lower substrate formed with a second electrode pattern having a second directionality are spaced from each other and an insulator is inserted therebetween in order to prevent the first electrode pattern from contacting the second electrode pattern. In addition, the upper substrate and the lower substrate are formed with electrode wirings connected to the electrode patterns. The electrode wirings transfer the change in capacitance generated in the first electrode pattern and the second electrode pattern by the touch on the touch screen to a controller.
With the recent increase in the efficiency of a multi-touch, research into increasing electrode patterns has been conducted in the capacitive touch screen. Accordingly, the number of the electrode wirings is also increased.
The capacitive touch screen according to the prior art forms the electrode patterns and the electrode wirings by separately configuring the upper substrate and the lower substrate, such that the configuration of the touch screen becomes complicated. A separate insulator is required in order to space the electrode patterns formed on the upper substrate and the lower substrate.
In addition, a portion of the capacitive touch screen according to the prior art is configured in a single layer structure rather than a double-layer structure. However, in the single-layer capacitive touch screen according to the prior art, the electrode patterns and the electrode wirings formed on the same plane have a complicated configuration, thereby causing a short-circuit between the electrode wirings.
In addition, the single-layer capacitive touch screen according to the prior art has several problems during the manufacturing process thereof. Since the electrode patterns and the electrode wirings are formed on the same member, damages occur on the electrode patterns when the electrode wirings are formed after the electrode patterns are formed or vice versa. In particular, when the electrode pattern is made of a conductive polymer and an etching process or an annealing process is performed while forming the electrode patterns, modification of the conductive polymer is generated to change sheet resistance in the electrode patterns.